Transfer ingredients to food processor or blender. Process until a smooth paste forms, about 30 seconds.

Add remaining oil and butter to skillet. Add onion, garlic and ginger paste. Cook 5 to 6 minutes more over medium high heat. Combine with spices and stir until aromatic, 1 to 2 minutes.

Add tomato paste and water. Stir. Bring sauce to a low boil and reduce heat. Simmer about 30 minutes, until sauce thickens. When done curry will be rich reddish brown with flecks of oil on the surface. If it is too intense, add yogurt.

Transfer ingredients to food processor or blender. Process until a smooth paste forms, about 30 seconds.

Add remaining oil and butter to skillet. Add onion, garlic and ginger paste. Cook 5 to 6 minutes more over medium high heat. Combine with spices and stir until aromatic, 1 to 2 minutes.

Add tomato paste and water. Stir. Bring sauce to a low boil and reduce heat. Simmer about 30 minutes, until sauce thickens. When done curry will be rich reddish brown with flecks of oil on the surface. If it is too intense, add yogurt.